In this exclusive interview with Radar Online, Jackson reveals she thinks Farrah wasn't mentally alert or focused enough to have signed an agreement last April that gave O'Neal control of Fawcett's cancer documentary. Farrah's Story aired on NBC last May, about six weeks before Fawcett died following her three-year battle with anal cancer.

"It caused me to become very sad and upset, when I saw that signed document, because I believed that she was not awake enough, because of the pain medication she required," Jackson said. "Frankly, to me, that document didn't look like she could have a clue what she was signing."

Last week, Jackson also told Radar Online that she was denied access to Fawcett—even via phone—in the brave blonde icon's final weeks. Reportedly, O'Neal and Stewart were staying at Fawcett's Los Angeles apartment during her final weeks.

"I am having a great deal of difficulty dealing with this," Jackson said. "It is very, very, upsetting and I can't see myself ever getting over it."